Reaching loader with guided lift cylinders



March 11, 1969 P. E. LA TENDRESSE 3,432,050

REACHING LOADER WITH GUIDED LIFT CYLINDERS Filed April 17, 1967 FIG 3 Mil 3e 39 44 INVENTOR.

PHILIP E4 LA TENDRESSE United States Patent 4 Claims ABSTRACT OF THE DISCLOSURE .In a reaching loader in which the boom is pivoted at the upper end of an upstanding reaching link, lateral stability is achieved through guidance of the lift cylinder assemblies which extend from the boom to the chassis. A U-shaped yoke, rigidly secured to each cylinder, slides along an arcuately shaped guide plate.

Introduction The invention of which this disclosure is offered for public dissemination in the event adequate patent protection is available, relates to material handling devices with reaching booms, commonly called reaching loaders."

A most successful type of reaching loader is that manufactured under La Tendresse Patent No. 2,788,139. In this patent, a boom which projects forwardly and carries a fork, bucket or other load-engaging device, is pivoted at its rear end to a reaching link. The reaching link in turn is pivoted to the vehicle chassis. A hydraulic cylinder assembly pivots the reaching link in order to move the boom forwardly in a reaching action. The boom can be raised and lowered by a hydraulic cylinder assembly which extends between the boom and the chassis in general parallelism with the reaching link. The hydraulic cylinders are in pairs, one on each side.

In spite of the fact that the reaching link would be a rigid member as wide as the vehicle and the boom would likewise be a rigid member as wide as the vehicle, there is a tendency in such a machine for sidesway of the boom. Various measures have been taken to limit the sidesway or to provide lateral stability. For example, the cab has sometimes been used as a guiding or limiting structure, the cab extending upwardly between two longitudinal side pieces of the boom. There has, however, been some danger attendant upon the shearing action which this type of guiding produced. Also it necessitated carrying the cab relatively high for guidance purposes, and this both increased the cost and necessitated high clearance. More recently, there has been very little eifort to provide lateral stability beyond that which careful engineering of the reach link and the boom and the connection between them could provide. It has been recognized, however, that close clearance between the inside of the lift cylinders and a portion of the. chassis along which the cylinders would swing gave some help in the direction of lateral stability. If for example, the boom should start to sway to the left, the right-hand lift cylinder would come into engagement with the chassis at a point far enough above the pivot point of the lift cylinder to add some tendency toward limiting the sidesway. There has long been recognition, however, that under adverse conditions this was inadequate. If, for example, the mobile loader should run on uneven ground so as to be tilted to one side, a heavy load will exert a very strong lateral force on the boom.

According to the present invention, a tremendous improvement in lateral stability is achieved by giving guidance to both lift cylinders in both lateral directions instead of in one, and at the same time raising the height of the guidance point. To this end a downwardly open U shaped 3,432,050 Patented Mar. 11, 1969 yoke is rigidly secured to each cylinder and straddles an arcuately shaped rigid plate which firmly guides the cylinder as it swings during the reaching movement of the boom.

Additional objects and advantages of the invention will be apparent from the following description and from the drawings.

Designation of figures FIGURE 1 is a view generally from the side of a reaching loader embodying the present invention;

FIGURE 2 is a fragmentary view looking in the forward-rearward direction so that the cooperation of the yoke and the guide plate and the mounting of the yoke to the cylinder can be seen;

FIGURE 3 is a generally horizontal sectional view taken transversely to the axis of the cylinder and looking down on the yoke and guide plate.

Intent clause Although the following disclosure offered for public dissemination is detailed to ensure adequacy and aid understanding, this is not intended to prejudice that purpose of a patent which is to cover each new inventive concept therein no matter how others may later disguise it by variations in form or additions or further improvements. The claims at the end hereof are intended as the chief aid toward this purpose, as it is these that meet the requirement of pointing out the parts, improvements, or combinations in which the inventive concepts are found.

Background description The reaching loader with which the invention is illustrated includes a pair of forks 11 comprising a loadengaging member 12 which is pivoted to boom 14 by pivot 16. The angularity of the load-engaging device 12 with respect to the boom 14 may be controlled by hydraulic cylinders 17. The boom- 14 is pivoted to a reach link 18 by a pivot 21, the reach link 18 being pivoted to the chassis 19' at pivot 20'. The boom can be raised and lowered by lift cylinders 22 pivoted to the chassis at 24, the cylinder assemblies including piston rods 26 which are pivoted to the boom structure at 27. The reach link 18 is a rigid member having uprights at opposite sides of the machine rigidly secured together as one pivoted unit. Likewise, the boom 14 has longitudinal members widely separated but rigidly secured together as one rigid unit. This rigidity goes a long way towards providing lateral stability for the boom, but not far enough for adverse conditions.

Reach cylinders 29 swing reach link 18 to make the boom 14 reach and retract. Lift cylinders 22 are swung by the boom, staying generally paralleled with reach link 18.

Double two-way guidance 07 present invention According to the present invention, a great deal of lateral reinforcing, or auxiliary lateral stability, is provided in the manner seen best in FIG. 2. Essentially, this comprises a U-shaped yoke 31 secured to each lift cylinder 22, the yoke straddling a guide plate 33 and moving along it. As seen in FIG. 1, the guide plate 33 is shaped arcuately along its top, the arc being described about the pivotal axis 24 of the lift cylinders. Preferably, the yoke 31 has a slight clearance with the guide plate 33, such as a sixteenth of an inch on both sides so that when there is no sidesway there will be no friction.

Yoke 31 preferably includes two U-shaped plates 36 welded to intermediate plates 37, 38 and 39, this whole assembly being welded to a member 41 which forms half of a split clamp 42. The split clamp may be tightened by screws 43 around cylinder 22. Rigidity of the attachment of the yoke assembly 31 to the clamp half 41 is aided by a pair of spacer rods 44 welded both to plate 39 and to clamp half 41.

Guide plate 33 is a very sturdy steel plate firmly secured to structural members of the chassis 19 by welding and braced by gusset plates 46, 47 and 48. Any gusset plates such as gwsset plates 46 between the two ends is spaced low enough on the guide plate 33 to clear the yoke 31.

Achievement The additional lateral stability provided by the present invention is very important. Without it, damage to the equipment due to sideward forces beyond the ability of the equipment to withstand was of sufficiently frequent occurrence to be a severe problem. Doubling the strength in resisting side play does much more than reduce the occasions of damage to half the frequency. It provides a degree of sturdinerss, a reserve of strength, such that damage from sideward forces is extremely rare.

I claim:

1. A reaching loader including a base frame, an upstanding link pivoted to the frame, a forwardly extending boom pivoted to the upper end of the upstanding link for a reaching movement as the link swings, and a lift cylinder means extending between the boom and the frame, swinging about an axis on the frame as the boom reaches; characterized by guide means for the lift cylinder means, as it swings, in-

cluding an upstanding guide plate rigid with the frame and having a free upwardly exposed edge arcuate about said axis, and a yoke straddling the edge and having bearing surfaces adapted to bear on opposite faces of the guide plate said yoke being rigidly secured to the lift cylinder means at a fixed distance from said axis.

2. A reaching loader including a mobile rough-terrain chassis, an upstanding link pivoted to the chassis and extending substantially the full width thereof, a forwardly extending boom pivoted to the upper end of the upstanding link, and extending substantially its full Width, for a reaching movement as the link swings, and a pair of lift cylinder assemblies extending between the boom and the chassis, one on each side of the chassis, pivoted to the chassis to swing about an axis on the chassis as the boom reaches, each assembly including a cylinder and a piston, characterized by guide means for each cylinder assembly, as it swings with the reaching boom, each said guide means restraining a portion of its lift cylinder at a point subment in either direction and through the lift cylinder exerting a force on the boom, when laterally displaced, for resisting sidesway of the boom.

3. A reaching loader including a mobile vehicle adapted for rough terrain and having a chassis frame, an upstanding link pivoted to the frame, a forwardly extending boom pivoted to the upper end of the upstanding link for a reaching movement as the link swings, and a lift cylinder means extending between the boom and the frame, swinging about an axis on the frame as the boom reaches; characterized by guide means for the lift cylinder means, as it swings, in-

cluding an upstanding guide plate rigid with the frame and having a free upwardly exposed edge arcuate about said axis, and a yoke straddling the edge and having bearing surfaces adapted to bear on opposite faces of the guide plate said yoke being rigidly secured to the lift cylinder means at a fixed distance from said axis.

4. A reaching loader including a mobile rough-terrain chassis, an upstanding link pivoted to the chassis and extending substantially the full width thereof, a forwardly extending boom pivoted to the upper end of the upstanding link, and extending substantially its full width, for a reaching movement as the link swings, and a pair of lift cylinder assemblies extending between the boom and the chassis, one on each side of the chassis, pivoted to the chassis to swing about an axis on the chassis as the boom reaches, each assembly including a cylinder and a piston, characterized by guide means for each cylinder assembly, as it swings with the reaching boom, each said guide means restraining a portion of its lift cylinder at a point substantially spaced from the axis against lateral movement in either direction;

each guide means including an upstanding guide plate rigid with the chassis and having a free upwardly exposed edge arcuate about the designated axis and a yoke straddling the edge and having bearing surfaces adapted to bear on opposite faces of the guide plate, said yoke being rigidly secured to its associated cylinder.

References Cited UNITED STATES PATENTS 2,471,364 5/1949 Weber 214439 2,788,139 4/1957 La Tendresse 214-14l 2,980,271 4/1961 Ulinski 214-770 HUGO O. SCHULZ, Primary Examiner.

US. Cl. X.R. 214770, 775 

